In a LR or in a RC Circuit, the voltage is always perpendicular to the current as shown:
In a RC circuit:
and in a LR circuit:
the different is in LR circuit, the current is ahead of potential difference and in case of RC circuit, it lags behind the potential difference.
In a normal resistive circuit, it is in phase with the potential.
thus in a LCR circuit, the current will be perpendicular to the potntial across the inductor and the capacitor and the potential across the inductor will lag behind the current by pi/2 and in capacitor, the current will lag by pi/2 behind the potential.
thus the phase digram will look like: