In the movie "The Pawnbroker", the actress who plays the woman who
invites the pawnbroker (played by Rod Steiger) to have lunch with her,
reminds me of the actress who plays a friend of Sophia that plans to
commit suicide in one TV episode of "The Golden Girls". Could these
two be one and the same?

Good afternoon rikki973-ga and thanks for the question.  I remember
watching the Golden Girls growing up and was excited to be able to
reminicse about the show while finding your answer, which I have
posted below.

The female cast of the Pawnbrokaer (1965) are as follows:

Geraldine Fitzgerald 
Thelma Oliver 
Marketta Kimbrell 
Linda Geiser

Source:  Rottentomatoes
( http://www.rottentomatoes.com/m/pawnbroker/cast_crew.php )


* * * * * * * * * * *

Geraldine Fitzgerald made a guest appearance  in the Golden Girl?s in
two episodes, the first one being the episode you referenced in your
question:

"The Golden Girls" playing "Martha Lamont" in episode: "Not Another
Monday" (episode # 5.7)
Originally aired: Saturday November 11, 1989 on NBC 
Writer: Gail Parent 
Director: Terry Hughes 
Guest Stars: Richard Mulligan (Dr. Harry Weston) , Geraldine
Fitzgerald (Martha) , Jayson Kane (Maitre d') , Bonnie Urseth (Mrs.
Lilastrand) , Doug Cox (Mr. Lilastrand) , Robert Neches (Bartender)
Production Code: 109 

Sophia's friend has come up with an idea that will change her life.
She wants to commit suicide and she wants Sophia there to hold her
hand. Meanwhile, Blanche, Rose and Dorothy become singing nursemaids
to a sick baby that they are taking care of for the weekend.

* * * * * * * * * * 

"The Golden Girls" playing "Anna" in episode: "Mother's Day" (episode # 3.25) 

Originally aired: Saturday May 7, 1988 on NBC 
Writer: Barry Fanaro, Mort Nathan 
Director: Terry Hughes 
Story: Kathy Speer, Terry Grossman 
Guest Stars: Alice Ghostley (Mrs. Zbornak) , Helen Kleeb (Margaret) ,
Wesley Mann (Jacob) , Geraldine Fitzgerald (Anna) , Terrence Evans
(Police Officer) , Lynnie Greene (Young Dorothy Zbornak) , Beatrice
Arthur (Grandma Petrillo)
Production Code: 076 


While waiting for phone calls from their children wishing them a happy
Mother's day, the girls reminisce about past Mother's days.

Source: TV.com
( http://www.tv.com/the-golden-girls/show/131/episode_listings.html&season=0 )

* * * * * * * * * * *

I hope this fully answers your question.  If anything needs
clarification, please ask!

Nenna-GA
Google Researcher

Nenna is 100% correct. Geraldine Fitzgerald's character in "The
Pawnbroker," Marilyn Birchfield, is the social worker who invites Sol
to meet her for lunch.

Thank you for the rating!  If you need anything else, please let me
know and I will do my best to help you!

Nenna-GA