Yes, they do have an Arlanda base, and they are short of crew there, however most of the Sterling crew are based at Copenhagen and they want to remain there, and with the current "overenskomst" agreement the company canīt force anyone away from their present base, they can only ask for volunteers or sling crew to ARN.
Unless you want to be treated with disrespect and contempt from management on a daily basis, do not join Sterling.
Have you tried applying to JetX/Primera, they are supposed to start operating 737-800 from ARN and GOT soon.
www.jetx.is