“Baroque (adj.): when you’re out of Monet” is a jocular statement (fake French for “broke—when you’re out of money”) that has been printed on many gift items, such as T-shirts, hats, buttons and cards, since at least 1996. “Baroque” is an artistic style that began about 1600 in Italy; Claude Monet (1840-1926) was a French impressionist painter.
   
 
5 September 1996, Garden City (KS) Telegram, “Read all about it—on a shirt” by Dolores Hope, pg. A4, col. 2:
Here’s a kind of egghead choice: “Baroque (adj.): When You Are Out of Monet.”
 
6 December 1996, Roanoke (VA) Times,  “Suits someone to a ‘T’”:
Baroque (adj.): When you are out of Monet.
   
Google Books
Galileo and the ‘Invention’ of Opera:
A Study in the Phenomenology of Consciousness
By Fred Kersten
Dordrecht; Boston, MA: Kluwer Academic Publishers
1997
Pg. IX:
In one of the shop windows I saw a sweatshirt with the word “Baroque (adj.)” in big black letters on the front. In the next line underneath in smaller letters was the definition: “When you are out of Monet.”
 
Google Books
The Psychology of Humor and Wit:
From Banana Peels to Viagra Jokes
By Donald M. Johnson
Santa Barbara, CA: Fithian Press
1999
Pg. 24:
A specialized example printed on a T-shirt was observed recently at the new Getty Center in Los Angeles: Baroque is when you are out of Monet.
 
Making jokes with homonyms is fun and inexpensive, a renewable resource
 
Google Books
Folly Beach:
A Lowcountry Tale
By Dorothea Benton Frank
New York, NY: HarperCollins Publishers
2011
Pg. 36:
“Baroque is when you’re out of Monet,” I said and Patti looked at me like I was crazy. “I have a T-shirt that says that.”