B. populneus does have side lobes on some leaves, as in this pic from my earlier calpoly link.
https://selectree.calpoly.edu/...
The weeping form of Mike's tree throws me off a bit but I did find a nursery site that showed a young tree and it was more weeping than the mature ones in the pictures. Not saying it's definitely B. populneus but apparently it is a species that is used in landscaping in Arizona.
