She has been covered occasionally in this thread at the Alexander Palace Time Machine Discussion Forum and nowhere else that I can find.
In a posting to the Alexander Palace Time Machine Discussion Forum on 17 November 2008, REMI stated, "She eloped with the Polish count Ignaz Gurowski from the convent where she was... Gurowski married her in Dover (England) in 1841. He fathered.... eight children, then he left his wife. The poor countess Gurowska died in a complete destitution in Paris. (Buried Montmartre cemetery). Her only surviving son, Fernando, was a cavalry colonel in Don Carlos VII. He was killed in 1875."
In a posting to the Alexander Palace Time Machine Discussion Forum on 17 November 2008, Yseult added, "Isabel was named Belita by her family - and all the members of the family were shocked when she eloped with Ignaz. At certain point of the history, they were settled in Brussels, where Belita received some help from the good queen Louise, wife of Leopold I. Later, poor Belita found herself alone and without a penny. She was dead after a long illness, as a hostess in a very humble hotel of Paris. The owner of the hotel adressed a letter to queen regnant María Cristina, explaining the deceased infanta has been unable to pay the bill during a few months. Obviously, the man hoped María Cristina would pay to avoid a scandal. But María Cristina adressed the same letter, with the bill, to Francisco de Asis (Isabel II's husband - gogm). I don't know if Francisco de Asis gave the money or not..."