Check out AustenProse.com for an insightful Q&A interview that Austen scholar Devoney Looser conducts with Whit Stillman.
Be sure to comment on that site as well to enter to win the novel.
In the article he discusses the title change, how he got to know Austen’s writings and how he wants to do another Austen film.
WS: Perhaps it is irrational but I always hated the title “Lady Susan” and, as you mention, so far as we know it was not Jane Austen’s; the surviving manuscript carries no title (the original binding was chopped off) and she had used “Susan” as the working title for “Northanger Abbey.” The whole trajectory of Austen’s improved versions of her works was from weak titles, often character names (which I know many film distributors hate as film titles*) toward strong, resonant nouns — either qualities or place names. “Elinor and Marianne” became Sense and Sensibility, “First Impressions” became Pride and Prejudice, “Susan” became Northanger Abbey. Persuasion and Mansfield Park are similarly sonorous.