How to simulate P-E loop of a lossy capacitor?
First, break out the ESR element as a separate element in your model. Now the Q variable is proportional to the voltage across the ideal capacitor part of the model, so it's easy to probe:



Now if you use an X-Y plot to plot the voltage across the whole (nonideal) capacitor vs the voltage across the ideal capacitor (again, as an analog of the charge variable), you'll get what you expect (with a bit of a starting transient as the first cycle gets started):



Some tips:


You need to simulate several cycles of the sinusoid to get the system to steady state.
You need to choose a frequency near the pole frequency \$1/(2\pi{}RC)\$. Too low and you won't be able to detect the hysteresis in the graph. Too high and you the hysteresis will get so opened up it will just look like the oval in your figure 1b.