The Nexus 4 is the latest Nexus device to climb aboard the Lollipop train. Google posted the factory image for the 2012 device today. The Nexus 5 and 10 and the Wi-Fi Nexus 7 have all gotten Lollipop, making the cellular versions of the Nexus 7 the only supported Nexus to not be updated.
Lollipop brings a host of improvements to Android and doesn't seem to hurt older devices that much, so it should do well on the Nexus 4. This is a factory image, which means applying it will require some command line work, and all the data from your phone will be deleted. If you don't like the sound of that, you can wait for the over-the-air update, which can take up to three weeks to hit your device.