The rotational dynamics of a supercooled model liquid of rigid [formula presented] dumbbells interacting via a Lennard-Jones potential is investigated along one single isobar. The time-temperature superposition principle, one key prediction of mode-coupling theory (MCT), was studied for the orientational correlation functions [formula presented] In agreement with previous studies we found that the scaling of [formula presented] in a narrow region at long times is better at high-[formula presented] values. However, on a wider time interval the scaling works fairly better at low-[formula presented] values. Consistently, we observed the remarkable temperature dependence of the rotational correlation time [formula presented] as a power law in [formula presented] over more than three orders of magnitude and the increasing deviations from that law on increasing l [formula presented] is the MCT critical temperature). For [formula presented] good agreement with the diffusion model is found. For lower temperatures the agreement becomes poorer, and the results are also only partially accounted for by the jump-rotation model. The angular Van Hove function shows that in this region a meaningful fraction of the sample reorientates by jumps of about [formula presented] The distribution of the waiting times in the angular sites cuts exponentially at long times. At lower temperatures it decays at short times as [formula presented] with [formula presented] at [formula presented] in analogy with the translational case. The breakdown of the Debye-Stokes-Einstein relation is observed at lower temperatures, where the rotational correlation times diverge more weakly than the viscosity. © 2001 The American Physical Society.