Snow Elves are the true natives of Skyrim. Snow Elves appear in The Elder Scrolls V: Skyrim add-on "The Elder Scrolls V: Dawnguard" as individuals who didn't live with the Dwemer but went into seclusion in a cave. Therefore, they were never poisoned nor did they "evolve" into the Falmer.
The Nords forced the other Snow Elves to live underground with the Dwemer who turned on the Snow Elves and fed them a poisoned fungus which made them blind. They are now known as the Falmer, creatures that do not like any other race except their own.
- Touching the Sky: Knight-Paladin Gelebor asks you to kill Arch-Curate Vyrthur to obtain Auriel's Bow