Where is this mentioned and if it is Raphael how does this fit with Raphael being Mac with his mantle gone walkabout?
In Proven Guilty, I believe. When Harry sees the warded room in the Carpenter house, Lash confirms it's angelic work. She says it's the work of "Rafael or one of his lieutenants".
As to the Raphael/Mac theory, there are several possibilities to explain it away, with varying degrees of likelihood.
1) Lash knows Raphael gave up his Grace, but doesn't know or believe that he'd truly leave himself powerless. She thinks he still could have done the work. (She's seen Mac through Harry's eyes, so the question is does she know who he is, and does she know he's completely powerless?)
2) Lash says Rafael out of immediate recognition, but then adds "or one of his lieutenants" as she remembers that he couldn't have. (She doesn't bother explaining, because it wouldn't do her any good to let Harry know he actually knows someone he could really talk to about having the imprint in his head.)
3) Rafael and Raphael aren't the same angel. She says it's angelic work, not archangelic, so it might be a lower tier angel. (A letter makes all the difference between Uriel and Ursiel. But it seems unlikely, as the names Raphael/Rafael have no difference in meaning, and you know how angels feel about their name and it's meaning.)
4) Lasciel fell just as humanity was getting it's start. As the theory has Raphael giving up his Grace after that, the specifics of his situation might not be known. (Same question as #1, did she recognize Mac and suspect what might have happened, and if so, did she stay silent out of self preservation?)
5) The theory is wrong, and Raphael is still active as an archangel.