So it fruits at Christmas, I would have to go immediately to clematines.
The only other "clue" that might mean something to me is that the petiole is flared and I do not see any thorns. BEyond that it looks like a citrus that yiou would find in a greenhouse in Canada. Not much exposure to citrus taxonomy.
Good observation mrtree! Didn't take long for someone to grab an obvious clue. This pic was taken at about 3 mos. so no thorns are visible yet. She's doing well and is about 3' tall now. 4 yrs old and first year fruiting currently. Clementine it is.