Hardy says that Hogan cured his hook by squaring the clubhead to the arc early in the swing, rather than delaying the squaring as much as possible by having the right elbow in front of the right hip. The whole issue of where the elbow is in relation to the hip is just an issue of how active your pivot is though, so that doesn't make much sense. The user that posted that clip also has the clip of Hogan in mexico where they show a slow mo closeup on his arms. There you can see that until about 10 oclock in the downswing he has done nothing with the clubface(whereas Hardy teaches you to square the clubface as the first move down). At that point Hogan starts bowing the left wrist hard. This bowing appears to get him from slightly too flat on the downswing to right on the impact plane.