Just speculation based on known lore.

Northern Elsweyr
http://www.visionwriters.com/wp-content/uploads/2010/11/1-palm-desert-palms.jpg
http://johnsonmatel.com/2011/September/GoiasNorth1/palm_landscape3.jpg
http://www.stevemaglio.com/badlands.jpg

Southern Elsweyr
http://www.touristmaker.com/images/new-zealand/glacier-and-subtropical-forest.jpg
http://4.bp.blogspot.com/_g0ax9YBjnHA/TMcTAUIBSQI/AAAAAAAACH0/ez4leoTVLCQ/s1600/Clouds+on+the+road+to+camili.jpg
http://www.touristmaker.com/images/new-zealand/new-zealand-forest.jpg

All the desert ones: yes. First forest one: Not at all, it's subtropical in a glacial area, doesn't strike me as Elsweyr. Second forest: No, looks more like Morrowind or Cyrodiil, I mean it's coniferous. Third forest: Looks more like Black Marsh or Cyrodiil according to the first pocket guide. None of them really look tropical enough. Here are some more like what I think Southern Elsweyr could be. http://thumbs.dreamstime.com/thumblarge_391/1240321957vM6IOD.jpg http://www.adventuredrop.com/CategoryImg/jungle.jpg http://media-cdn.tripadvisor.com/media/photo-s/01/24/a0/ff/waterfall-in-rain-forest.jpg http://static5.depositphotos.com/1031174/401/i/950/depositphotos_4018390-Jungle.jpg http://www.kriyayoga.com/wallpapers/widescreen_wallpapers/jungle-vegetation/jungle-dsc04039-ws.jpg

North, defiantly. Southern, not so much.

UESP said subtropical forest so I googled it.

http://www.uesp.net/wiki/Lore:Elsweyr
The northern part of Elsweyr contains arid badlands; the southern part is a lush sub-tropical environment with many forests. Only a few cities have been established, and most of the settlements are small villages.

https://www.google.com/search?rlz=1C1CHKZ_enUS433US433&gcx=w&q=subtropical+forest&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&biw=1920&bih=955&sei=Vd7UTveDBo-4twfAuqCkAg

Hmm, where did they get that? I had heard it was tropical but I admit I don't have a source for it. The only source UESP cites is the pocket guide, which doesn't seem to have the word anywhere in it. I guess I just imagined a country that far South (in what is obviously the northern hemisphere of a planet) that had a barren desert to the North (and in fact, there are deserts further North, so it must be fairly Southern), would be tropical rather than subtropical, certainly not coniferous anyway. Just doesn't look right. I imagine Cyrodiil in it's earlier description would have been a subtropical forest.

Most likely that near the border of Valenwood, it has to be forested. This doesn't help as the said border keep changing back and forth, due to war with both races and how one of the sub-specie of the Khajiit, the Ohmes, look nearly identical to the Bosmer.

you want to know what elsweyr could look like? look up the oblivion mod deserts of anequina (not sure about the spelling) and be sure to have a change of pants ready.

http://www.tesnexus.com/downloads/file.php?id=25023#content
this did a great job at it