Armature problem

Hi everyone,

My problem is how to rotate the arm of the body from the shoulder.
I added an armature along the forearm, I did a Ctrl + J, then I selected the body and the bones, and I did a Ctrl + P (with automatics wheight).
I put in Pose mode, but the bones does not move the arm (the sleeve).

Here is the image corresponding to my question:

Thanks for your help,