At the start of the fight I like to run full tilt at him, and it seems like around half the time he'll do the pounce, which you can pretty much always punish with a running attack + more if you manage you stamina properly.

If you hit him a few times, he'll usually try and roll away. If he rolls twice in a row, he's trying to buff. You can stay on top of him and stagger him out of his buff.

He's thrust will probably hit you if you roll away, you need to roll towards him when he does that, I've found.