Nope, unfortunately you can't.
The bike stations at Lysaker and Fornebu appear similar to the ones in Oslo, but the bike system which belongs to the Municipality of Bærum, and is not integrated with the system in Oslo. It's not possible to park or unlock a bike from these bike stations.
You can see the stations you can use as an Oslo City biker in the app and the map on out webpage: https://oslobysykkel.no/en/map
If a bike gets parked in a station that belongs to Bærum, it must be picked up by operating crew from Bærum. This steals a lot of time from us and them, in addition to making the bike unavailable to other city bikers, so we kindly ask you to not do that.