A quick update to those Nexus 4 users clambering for a chance to use Lollipop: a factory image is now available.
Build LRX21T is now available to download, though flashing a factory image will overwrite all of your apps and data. When flashing, ensure to back up all of your important media and be ready to log in to all those accounts again.
More patient individuals can wait until Google rolls out an over-the-air update to the Nexus 4, which should arrive over the coming weeks.
Source: Google Developers