walk or foul?

[peteraus]

Hi there can anyone give me a definitive answer on the following?

Fastball. Batter in the box. Ball is pitched. It is inside. Batter attempts to avoid being hit. The ball hits the batter on the arm just below the elbow and bounces off and hits the bat. Umpire calls foul. Given that the ball hit the batter first should it not be a walk.
Umpire claims that whether the ball hit the batter's arm first is irrelevant. Walk or foul?

Regards,

Pete