Lugh *luek-

I have seen Lugh as coming from *leuk- on several websites. Almost
always with a footnote saying that there is some problem getting Lugh
or Lugus from the *leuk- root.

I have no problem believing that there is no connection between the
two but could someone explain the difficutly in linking these two
together? Is it that the PIE k would not give us a g sound? if that
is so then why?

thanks in advance
Ken