Sorensen family

My name is William E. Sorensen and I am looking for birth records from Oslo Norway for a " Wihelm Toralf Sorensen" William R. Sorensen he was born in 1902. He left Norway after his parents left each other and came to the U.S. to find his mother who moved to New York City years before. He used to tell me that when he was a young boy he used to play with the king of Norways son "Olav" so he must have lived near by. I can be reached at [email hidden] U.S.A.