It's funny, power steering fluid seepage never dawned on me as a probable culprit. It's funny especially because, as one of those "while I'm here" items, I did check the level. It was good. But I didn't look closely around the fill opening to see if there had been any leakage. And, of course, everything's closed up again at this point
I can probably take another gander at it before the end of the week...