$$Cl_H = Q_H \cdot HER$$
The HER is the proportion of drug that is cleared from hepatic blood by the liver:
$$HER = \frac{C_{in} - C_{out}}{C_{in}} = 1 - \frac{C_{out}}{C_{in}}$$
Note that 1 - HER gives the bio-availability.
What determines the HER? From a mass balance:
$$\text{Mass into liver} = \text{mass in hepatic vein}+\text{mass metabolized}$$
$$C_{in} \cdot Q = C_{out} \cdot (Q + CL_{int})$$
$$C_{out} = \frac{C_{in} \cdot Q}{Q + CL_{int}}$$
And then from the definition of HER we have
$$HER = 1 - \frac{C_{in} \cdot Q}{C_{in}(Q + CL_{int})}$$
$$HER = 1 - \frac{Q}{Q + CL_{int}}$$
And a funky algebra move gets us
$$HER = \frac{CL_{int}}{Q + CL_{int}}$$
But we're usually dealing with protein bound drugs, so we have to account for the fraction unbound:
$$HER = \frac{F_u CL_{int}}{Q + F_u CL_{int}}$$
$$Cl_H = \frac{Q F_u CL_{int}}{Q + F_u CL_{int}}$$
When intrinsic clearance is very low, such that it is much smaller than Q,
$$Cl_H = \frac{Q F_u CL_{int}}{Q}$$
$$Cl_H = F_u CL_{int}$$
then clearance does not depend on hepatic blood flow, only intrinsic clearance and fraction unbound
When the intrinsic clearance is very high, such that it is much larger than Q,
$$Cl_H \approx \frac{Q F_u CL_{int}}{F_u CL_{int}}$$
$$Cl_H \approx Q$$
then clearance is close to hepatic blood flow, and the fraction unbound and intrinsic clearance do not matter.
High intrinsic clearance drugs: GTN, lidocaine, ketamine, propofol, morphine
Low intrinsic clearance drugs: warfarin, diazepam, rocuronium