[lagster]

is the left arm rotation a conscious,deliberate efort?

/////////////////////////////////////////////////

In the Backswing this is called TURN, and the Downswing ROLL. Then, there is the Swivel. These are all different things, with different identities.

TURN-- IS A PRONATION OF THE LEFT FOREARM. This can be done consciously, especially when learning. A Swinger, using Standard Wrist Action does this.

SWIVEL-- With Standard Wrist Action on the downswing, the Left ARM(Wrist) remains Turned, until the Release Swivel, which happens very quickly, takes the Flat Left Wrist into Impact.

ROLL-- IS A SUPINATION OF THE LEFT FOREARM(Flat Left Wrist). This(with Standard Wrist Action) happens after Impact. Horizontal Hinging... FEELS like a Full Roll.

All these motions can be done "consciously" until learned. With proper practice, these motions should become smooth, and more Automatic.