Continue to halfway back, where the left arm is parallel to the ground and stop, as shown above. By now the wrists should have hinged so that the club is vertical and the left arm should still be straight. From here, rotate your shoulders to get the club to the top of the backswing.
Try rotating your shoulders as much as possible whilst also trying to limit your hip rotation, to really feel the muscles in your left arm and upper body working hard.
Hit a few balls from this position and feel the speed as you swing down!