I'm descended from a Carl Victor Wallström (1866-1944) from Lerbäck parish (Mariedamm is located real close) in Sweden. He came over in 1887 and settled in Stockholm, WI. He changed his name when he arrived here to Wahlstrom. His father's surname wasAndersson but he changed his name prior to 1863 (over in Sweden) to the last name of Wallström.
There is a page that seems to deal with the Wahlstrom surname, it's address is http://freeweb.pdq.net/daw/family/wahlstrom/Happy searching!