I'm confused! <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />
I have seen all of the following:
Elf: Elves - Elfs; elven - elfen -elfish
Dwarf: Dwarves - Dwarfs; dwarven - (not dwarfen or dwarfish, though)
What is considered correct spelling <img src="/ubbthreads/images/graemlins/question.gif" alt="" />
You can blame Tolkien for this one. The originally correct English version is 'Elfs' and 'Dwarfs' but Tolkien disliked these spellings, so he chose to use 'Elves' and 'Dwarves' to indicate his races instead.
As Tolkien has basically redefined everything concerning those races as far as the English consciousness is concerned, his spellings are now so universally used that the language has functionally been changed so that his spellings are just as correct as the originals. In time, I suspect, the original spellings will be discarded entirely.
Language, after all, changes with use <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />