Watch the Sonora Spring: Intro & Chorus online guitar lesson by John Jorgenson from Gypsy Jazz Journeys: Sonora Spring
Here's the second phrase of the chorus of "Sonora Spring". This is now going from the D chord, moving to the C chord. It all happens on the B, G, and D strings.
Something that happens quite often in gypsy jazz is you'll get two notes on a string, and I imagine that's partially because Django Reinhardt only has use of the first two fingers on his left hand, so he did almost all of his solo work using only his index and middle fingers. I use that technique some, but I throw my other fingers in as well.
So, the phrase is a D arpeggio in scale, starting out on the 10th fret going to the 7th on the B string, then the 9th to the 7th on the G string, and then the 9th to the 7th on the D string. You're picking down-up on each of the three strings, and then you jump back to the B string and do a scale going down. Put them together and you'll have the phrase. A little bit tricky, but you'll get it with practice.