From LOVECRAFT AT LAST by William Conover: Lovecraft said, "Comte d'Erlette's Culte des Goules? An invention of Bloch's. The name Comte d'Erlette, however, represents an actual (and harmless) ancestor of August W. Derleth's, who was a royalist emigre from France in 1792 and became naturalised in Germany under the slightly Teutonised name of Derleth. His son, emigrating to Wisconsin in 1835, was the founder of the Derleth line in America."
("The Haunter of the Dark," "The Shadow Out of Time")