Starting with a fresh configuration several times in the course of various experiments this evening, I notice that LW (I am using v3.9.10 right now) apparently defaults to function as a leaf rather than a Ultra Peer, even though Disable UP is by default unchecked in the options.

To get around this, I checked this option, saved options, then unchecked it, save again, and then disconnected and reconnected. LW then (nearly instantly) connected as a UP.