I have and it does not say who exactly the Dwemer are. There is a lot of speculation and assumptions.
All we really know is that they were from Mer descent.
They were already living in Morrowind when the Chimer (the race of mer that eventually became the Dunmer) arrived to settle there, which was (IIRC) in the first era or even prior to that.
The Orsimer first appeared on the other side of Tamriel, around the same time or shortly after the Chimer settled in Vvardenfell. The two races (Orsimer and Dwemer) co-existed for several centuries.
I highly suggest you go read the UESPwiki's articles on http://www.uesp.net/wiki/Lore:Dwemer and http://www.uesp.net/wiki/Lore:Orc. They're not the same race and pretty well can't be, given that they co-existed. The only similarity is that they're both mers...although with the orcs that's up for debate.
Also, we've seen images of the Dwemer. There are statues scattered across Vvardenfell, outside their ruins, and you http://www.uesp.net/wiki/File:TR_Creature_RadacStungnthumz.jpg at one point during Tribunal. They resemble the other mer races much more than they do the Orcs, to me.
Divayth Fyr CLAIMING he is the last Dwemer? Not going to cut it.
Divayth Fyr isn't the only one who claims that. Yagrum Bagarn himself will tell you the same, and corprus or no, I'm inclined to believe him. He has the cred to back it up, and if you bring him some specific Morrowind texts that are written in Dwemeris, he's capable of translating them and has some good insights to share with you.
TL;DR: Dwemer are not Orcs. Go play Morrowind. The Dwemer culture is very well explored there, although their disappearance is still a subject of debate.