When it comes to the contact and getting the club to hit the ground in the right spot at the bottom of the arc of the swing, your arms need to be as extended as necessary. They don't have to be, iron bar straight. They just need to be extended enough for the club to hit the ground and interact in the right place. Now, a lot of people separate their elbows. So here's a drill that's going to help you stop doing that because you're going to have to fight against it.

I've got my thumbs through a resistance band and I've tied a loop in either end. So it stays attached to my thumbs, and I'm going to wrap it round the middle of my back. Now, when I take my grip, the first thing that is going to happen is when I put my arms down, a band is going to stretch. So if I relax, it's going to want to pull them together, and when it pulls the club back up, see how my arms and elbows separate. This is a big issue when it comes to not having your arms extended enough when it comes to impact.