[Wynton]

With regard to raising the flop and/or turn, the question is not just whether it protects his hand, but whether he's ahead. If you assume the villain will call with a worse hand, then why not raise?

Having said that, I see value to waiting till the river to raise. I think that depends on the opponent.

Now as to the question "what if raised on turn," I fold. But that's because I'm playing 2/4 and 3/6. At those limits, I am convinced the turn raise is so rarely a bluff that it is hardly worth considering. Might be entirely different at 5/10.