On one ticket I would not worry at all. OSL is very efficient. ARN will also be OK. And this is independently of whether you have checked luggage or not. On short connections in the past I experienced the cases, when my luggage made it but I did not (yes, I know that this is weird).

OSL is only slow if you are connecting to a domestic flight.

And Ksu is right: do not even think to do this if you have important meeting just after arrival, or if you are travelling on separate tickets.