Based on his letters from Harlan Ellison, I believe Patrick attended the very first Clarion Science Fiction Writer’s Workshop in 1968. I visited the Clarion web site a couple of days ago and realized that his name was not included on the list of alumni. I wrote to them about it and a very kind person (also named Patrick) quickly added him to the roster. You’ll find him listed alphabetically by last name, just after Vonda McIntyre.