Originally Posted by
Ryllharu
It's been mentioned over and over during conversations with Suzaku that everyone thought he was in the Research Division, in a non-combatant role. He never lied to anyone about it, he always just said "research division." Everyone simply assumed the rest. This became clear when his cockpit was cleaved open and the reporters were all in shock that an Eleven was piloting a Knightmare, not to mention the most advanced one. It would be a huge shame upon Britannia if Euphie hadn't to saved it by declaring him her personal Knight. I'm sure she wanted to do it anyway, but there was not better time.
So Lulu hasn't been ignoring Suzaku, he honestly didn't believe his friend would be piloting a Knightmare, since he had no reason no to believe Suzaku's story about being a non-combatant.