CHRISTENSEN, Hans Ingvard of Helsingor Denmark

I am searching for information on my grandfathers family.HANS INGVARD CHRISTENSON was born in Helsingor Denmark (Sjaelland Island - northern part).Hans was born on May 17, 1900 and had a twin sister.Both Hans and his sister were adopted at about age 5 years.Their birth mother's name was MAREN KRISTINE CHRISTENSEN.Hans was in the Danish army for approximately 4 years.He travelled to Canada when he was about 24 years of age.Upon arriving in Canada his surname was changed by accident by Canadian Officials (Christenson).
Any information would be appreciated.