After they part in the park, O'Hara hears a cry for help and rescues Elsa from a group of hooligans. She gratefully lets him take her to a nearby garage where her car is parked. She tells him she is married to Arthur Bannister, a famous, perhaps infamous, criminal lawyer.
Then ... On the way to the garage they almost collide with a cab and receive an earful from the driver.
... and Now, this looks like a set and indeed it is - it was filmed on the Columbia Ranch back lot in Burbank in Southern California (map). The ranch is still operational, now known as the Warner Ranch. Below is a contemporaneous image from another movie showing the same street corner, with some minor changes, on the ranch's New York Street.
Then ... They alight from the buggy and walk past the Ellery Apt Hotel. One clue to its location is the number 1028 on the name plaque ...
The location was revealed to CitySleuth by John Bengtson, who hosts a well-researched silent movie website. Per John, this was on Hope Street in Los Angeles and sure enough the 1956 L.A. city directory confirms that this was indeed a real building at 1028 S. Hope Street.
... and Now, the hotel has been demolished - its site is now a parking lot whose entrance is about where the hotel entrance was
Then ... Elsa's car, a swanky 1946 Lincoln Continental V-12 convertible, is parked at a garage next to the Ellery hotel. They banter awhile then she asks him... "If you're a sailor Michael there's a job for you - would you like to work for me?"... then, suggestively, "I'd like it". She is to ship out with her husband the next day to the west coast by way of the Panama Canal but her yacht is short one crew member. "I'll make it worth your while". Hmmm. She looks surprised when he declines.
... and Now, the garage was next to, perhaps part of, the Earle C. Anthony Packard dealership at 1000 S. Hope (it too is listed in the city directory above). There's still a garage at this location, part of the Packard Lofts building that was built in 2006 on the site of the dealership.
Then ... But O'Hara has a change of heart after Arthur Bannister himself pays him a visit and he shows up at a yacht harbor to join the crew.
... and Now, this was filmed not in New York but near the 22nd Street Landing restaurant in San Pedro, Southern California (map). This recent photo shows the distant breakwater on the right and the concrete pilings to the left, visible Then and Now.