You need more training on the flat days watching more youporn or worldsex. That will get the forarms back in shape.
I had a bit of arm / shoulder pain and someone suggested puting the computer mouse on the left hand side to see if that made a difference.
Something about tensing your forearm while operating the mouse and hunching over while using the computer (bad for neck too).
It feels a bit awkward first up, but you get used to it.
I'm not sure if that is what helped, but it did make me aware of the muscle tensions that are operating when you are doing something as simple as working on your computer, and made me more conscious of the bad posture and having a stretch every now and them.
Anyway, problem seems a lot better since.
, missing out on WS sessions now. 
So I did a session with a physio and he found that my shoulder, neck back muscles were quite bound up and probably causing ciculation problems down the arm.
My range of movement, head shoulders was poor and I could feel how tight things were. I think that sitting at the PC and stress were big culprits
In addition to some massage and manipulation of neck, shoulder and arm, the Physio has given me some exercises to help loosen up nech and shoulders. He said that I needed to fix this before focusing on the elbow.
I gotta say today's sailing session felt much better, my arm didn't get as sore, despite powering aound on a 7.8m sail in 15-25 knots. So at the moment I'm feeling positive
Ok I know nothing about Tennis Elbow, actually I know nothing about a lot of things 
But I have had Golfer's Elbow, Doc said give windsurfing away for god knows how long, bugger that. Made me think what am I doing different, then I remembered some clown talking me into shorter harness lines (22") and realizing that's when my woes slowly began. Soooooooo I went back to 26" and my elbow started to come good. After talking to the Mighty Elmo re going faster I now use 28's, perfect and no elbow problems.
Ok I'm no Doc but if you have short lines maybe longer might help, who knows 
You put the mozz on me. Got my first ever case of windsurfing elbow after a session yesterday. Built a new side fence about 3 weeks ago and felt numb in the fingers after hammering all the pickets on, but after yesterday's W.S session I can't even turn the car ignition on as my right forearm is so weak and sore. Will go to physio, (david, in bluff Rd sandringham) later in the week and keep you informed if I think he is doing any good. Can never be sure if spending those $ helps.
Went to the chiro today & she said that training your body to use its core muscles for things is the way to go. She gave me exercises to do to ' reprogram my brain to use other muscles' . I know it works as until recently when i did the exercises my core stomach muscles would switch on. Ive got slack & haven't been doing them as much lately and now my neck muscles switch on instead ( lying on back raising legs ) which was the problem earlier..Anyway what I'm trying to say is that she says if your core muscles are used to do things the strain/ pull comes from your core rather than your arms so less strain & everyones happy..
So a set of exercises specific for you from a good chiro or plitaes will prob help long term..
Here is a tip for you.
Latin dancing will do all that stuff and more, especially the proprioceptive stuff, and it's a lot more fun.
Can't dance ??
Google "Core Rhythms"
The latest research shows that cortisone injections, whilst being very effective for immediate and medium term relief, increases the long term morbidity of the condition. See link.
www.bbc.co.uk/news/health-11598090
On the issue of computer use - I got a v. bad case of tennis elbow from tennis a couple of years back. Made no progress in healing it for the first four months, despite sport rest.
Finally went to the physio and we agreed to swap the mouse to the left hand side, and wear the elbow brace thingy while typing at the computer, which I do a lot of for work.
Improvement commenced immediately. Took a year to fully heal. Interestingly, after about the first 3 months, I found windsurfing (with the brace) seemed to do it good (all that pumping - the tendon that is the culprit has a poor blood supply).
