I’d like to offer advise, but unless I see all of your swing and what is going with your total body, I’d be speculating. A straight arm is a result of other actions (not something you do). One thing I can tell you, is that after impact, your front arm elbow (left arm elbow for a right hander) will point towards the ground and fold for the back arm to straighten out. If your elbow is pointing out, more than likely you have the “chicken wing” action. Many times this if from the body not rotating all the way to the finish and the arms try to help by and pull across the body. This can cause your toe hit… but keep in mind, there are other reasons for a toe hit too.