[Lingo] explanation for いなくて寂しい

[steve <sjs@example.com>]

Hi all

Can someone explain this expression to me.  Since いなくて is the 
negative te form of いる and 寂しい means lonely, it seems like
いなくて＋寂しい should mean "to be not + lonely."  Is this just one of 
those quirks of the language or am I missing something?

Thanks
Steve Smith