The white shirt is part of his uniform? When he casualwears, he just goes for a turtleneck black. Just the way uniforms works in Japan and they seem to emulate that...
However, if you want to read it as a symbol, it works : Lelouch's 'white' self (a symbol of his childhood self?) is not really completely gone. It's just hidden behind that black form he 'must' wear. (Being a uniform and all, a symbol of the self he puts forward?) But he's shown in his white shirt when planning something he's not quite honest about (5, 9, 22), which indicates his reluctance to give in to either side.
(no subject)
However, if you want to read it as a symbol, it works : Lelouch's 'white' self (a symbol of his childhood self?) is not really completely gone. It's just hidden behind that black form he 'must' wear. (Being a uniform and all, a symbol of the self he puts forward?) But he's shown in his white shirt when planning something he's not quite honest about (5, 9, 22), which indicates his reluctance to give in to either side.
/overanalyze