Don't panic! Despite the original Lollipop announcement stating the update would "be available on Nexus 5, 7, 10 and Google Play edition devices in the coming weeks," it looks like Nexus 4 owners won't be left out in the cold after all.
Googler Sascha Prüter clarifies in a Google+ post that the Nexus 4's conspicuous absense is "just a mistake." Indeed, the error is already fixed. There's no specific word on timing, but if history is anything to go by, the N4 will fall right in line with the rest of the Nexus updates soon enough.