* "We fortuitously found a parking spot right in front of the restaurant, which was a rare occurrence on this busy street." (meaning: luckily, by chance)
* "The hikers fortuitously stumbled upon a hidden waterfall during their exploration of the wilderness." (meaning: by chance, luckily)
* "The scientist's fortuitous discovery of a new element led to a breakthrough in the field of medicine." (meaning: by chance, luckily)
* "It was fortuitous that the storm arrived after the concert ended, as it meant everyone was able to get home safely." (meaning: luckily, by chance)
* "The artist's fortuitous meeting with a famous collector led to her work being displayed in prestigious galleries." (meaning: luckily, by chance)
Remember that "fortuitously" implies something happening by chance, but in a positive or beneficial way.