The invention relates to a ballast arrangement for igniting and operating a discharge lamp. The lamp is connected in a commutating bridge in series with an inductor and in parallel with a capacitor. The conductor and the capacitor jointly form a resonance circuit during an ignition phase. The bridge is then commutated at a comparatively high frequency. After the ignition phase, the lamp reaches a run-up phase, leading to a stable-operation phase. In the stable-operation phase, the bridge is commutated at a low frequency. According to the invention, the commutation frequency is lowered in steps from the comparatively high frequency during the ignition phase to the low frequency of the stable-operation phase so as to optimize current supply during the run-up phase.