Can You Lend A Hand, Dear Blog Reader ?

Hello there. I'm working on poem eleven, which is to do with John McGahern's Memoir. I'd begun it back in December, and it's a collage of things people have said to me about reading the book, or thinking about reading the book, or what they have heard about the book and so on. The poem will start high on the wall in the Dock, right below the clerestory windows and will read vertically down the wall and then fall onto the stairs.

But there's a missing piece, and I wonder if anyone out there can help me. Somewhere in the last year or so in all the press coverage about the book, I read that McGahern said something like this about writing it (this is rough memory at work here): "I sit down at the desk and when the tears start to flow, that's when I write." Something like that. Can you tell me where I read this?
Thanks. Alice