Luther didn't hear the Ravenclaw, who he was almost sure was named Ashley, approaching. He was too focused on basking in the warm spring weather. That's why he was startled slightly when he heard her speaking.

Turning around, he saw her setting up her equipment to paint, Luther assumed. "Oh, hello Ashley." said Luther waiting for a moment to see if he got the name right and then continued "I... I was just enjoying the weather." then pointing to her art supplies, "Am I blocking your subject? I didn't know you liked painting." and moved to side.