Ivory Silk Lilac Tree is what's out front of the house

At least, based on the tag of another same-looking tree just down the sidewalk.  

"Ivory Silk Lilac Tree -- Syringa reticulata Ivory Silk -- Full Sun -- Zone 3 -- H: 8m -- W: 5m -- Creamy white large size flowers in May-June, disease resistant"

(This is the tree that was planted ~3-4 years ago, that the song sparrow is often in this year.)