I have NEVER been able to accomplish a 'provisional cast on' using a knitting needle and crochet hook. Besides being completely left-handed, I'm an utterly inept crocheter.
My smart sister Susna suggested Lucy Neatby's video on how to do the PCO (that's Lucy over there, not Susna!) By golly, I did it! Not that I wasn't still a total spaz with the crochet hook, but I actually did it! Yay and thanks, Lucy!