Originally Posted by
Koby
I doubt that there even is one (officially), since BCN is not a hub for them.
But you'll need maximum 10 minutes (for a good walker) to get to your next gate, and no security in between. (Also, the gates that the LH group uses are more or less grouped together, in my experience.)
So it seems, a 45 min connection (OS>LH, no luggage) would be doable, assuming no inbound flight delay then.