Although “elven” is given in OED as

Comb. (referring to a kind of imaginary being in the works of J. R. R. Tolkien).

of the examples provided, this is not one.

• 15.033 of elven-harps

“ˈelven, n.” OED Online, Oxford University Press, June 2017, http://www.oed.com/view/Entry/60661. Accessed 13 September 2017.