Lux vs Sivir spell shield

Sivir's spell shield can block more than one spell. I noticed this with Lux not sure if it works with others. Lux's combo is q e r, but while you lay your e before your r you explode it after you r. If you r and press e while you're shooting your laser then the e explodes pretty much the same time as your r. so if sivir procs her spell shield it blocks both the e and the r