Google just released Android 5.0 Lollipop factory image for Nexus 4. The OTA (over-the-air) update will take some times to reach your phone, however, if you cannot wait for the OTA update, you can download the Lollipop factory image and binaries for Nexus 4 (firmware build LRX21T) and install it manually via fastboot.
If you would like to update your Nexus 4 to official Android 5.0 Lollipop (Build: LRX21T) manually, here is an easy to follow guide. However, keep in mind that, installing the factory image will wipe everything on your phone, so before flashing the firmware, backup any important files (contacts, SMS, etc.)
Disclaimer: Please follow this guide at your own risk. We will not take responsibility for anything that goes wrong. This guide is intended for technically talented users only
1. Before you get start with, make sure your nexus 4 has unlocked bootloader
2. Download [HERE] Android 5.0 Lollipop factory image (LRX21T) for Nexus 4 and extract the file (occam-lrx21t-factory-51cee750.tar). You will get below files.
3. Install ADB, Fastboot, and driver on your computer (Read this super easy method).
4. Copy all the firmware files to the same folder as the ADB and Fastboot
5. Now, boot your Nexus 4 into fastboot mode. To do so, switch off your phone and press and hold Power + Vol up for a few seconds.
6. Connect your Nexus 4 to PC via original USB cable
7. If you are on Windows PC, run the “flash-all.bat” file from the files you extracted in Step 2 (on Mac, run the file “flash-all.sh” using Terminal and on Linux, run the file “flash-all.sh”.)
It will take some times to complete the process. Once the installation process is completed, your Nexus 4 will automatically reboot to Android 5.0 Lollipop. (Source)