Celia - I'm going to add a word of 2020's caution - one of the reasons for the resurgence in tennis elbow is the cell phone - really! We sit, often on a sofa, in a recliner, or at the table, phone propped in one bent arm, the other pecking away at the keyboard...and pretty soon that bent elbow is sooo... sore. Please pay attention to body mechanics and see if you can find that cause for your own arm, otherwise all the exercises in the world won't fix you.
Sue