How format nexus 4 before flashing new ROM

I have a Google Nexus 4 (mako) and I had installed cyanogen mode which accidentally showed a loop error message like "... has unfortunately closed" telling that several google apps and wizards had been closed.

What I tried to DO:

Now I want to re-install cyanogen. Because cyanogen is outdated I decided to flash the latest lineage ROM. My recovery (CWM version 6) is still unlocked, so I decided to do the fallowing:

1. Turn off the device


2. Go into boot loader mode by pressing Volume down and power and selecting to start recovery mode.


3. Wipe Data / Factory Reset


4. Enter side load mode and install lineage:
   adb sideload lineage-*.zip


5. Reboot.

After that lineage os booted and showed the same errors than my old cyanogen ROM. There are even error messages regarding some google apps, although they are not installed.

Possible solution:

It seems that the wipe data / factory reset did not delete the whole cyanogen mod. It seems just to delete user data. I think I need to format the whole device. Last time this maybe was done while unlocking the boot loader.

Question:

How to format Nexus 4 before flashing a new ROM.