It appears we both may be right.
According to
http://en.wikipedia.org/wiki/Paul_Lacroix,
Paul Lacroix (April 27, 1806 - October 16, 1884), French author and journalist, was born in Paris, the son of a novelist.
He is best known under his pseudonym of P.L. Jacob, bibliophile, or Bibliophile Jacob.
By the way, it seems the initials 'P.L.' stand for 'Paul Lacroix'. Hopefully this clarifies the issue for those so inclined.
-Nick