Beautfiul plant. Looks a little like the variety volkii. L. pseudotruncatella was the first lithops species I grew. I must have went for the biggest lithops available. Then I learned they tended to stay as a single headed plant, and I changed to L. lesliei :). No flowers on my lithops yet. I think several L. bromfeldii plants are beginning to push buds up. Your pseudotruncatella is a nice big plant, with a nice big flower! Very nice.
It has also been suggested that it is groendrayensis. The Conophytums seem to have started flowering early this year and I have already had more Cono. flowers than Lithops which seems odd.