I misread Ilon as
Ilan until I spotted your query - thanks!
Ilan is in the db all right, and so it should be. Plus, among the Comments I found this:
Variant spellings:
Alon, Eilan, Eilon, Elan,
Elon, Ilon.
--
Nisha 1/30/2013
How reliable
Nisha might be, of course, one does not know. But it seems convincing. The other apparent alternative - a masculine version of
Ilona - isn't very likely.