Would A Cortisone Shot Help For Tennis Elbow?

I have pain in my right arm that has been diagnosed as "tennis elbow" - it hurts all the time with no relief. "Aleve" helps a bit but not entirely. Would a cortisone shot help and if so, for how long?
I am 62, female, 120 lb. , 5ft.6 1/2 inches -
I did have a cortisone shot in my right shoulder 2 years ago for rotator cuff problems - helped immensely.