From tsuwm's wwftd:

Quinion notwithstanding, (http://www.quinion.com/words/qa/qa-beg1.htm) I never heard begs the question used in a way that I would have interpreted as meaning raises the question. I've always interpreted the much maligned usage as meaning avoids the question. The idea that the question should be asked is merely a natural consequence of its being ignored, given the context of the situation in which it has been ignored. This usage (avoids the question) is well within the accepted definition of beg. See def 3a in AHD http://www.bartleby.com/61/4/B0160400.html.

I do like his comment that the person who translated [petitio principii] made a hash of it.