the invention describes a method of driving an arc - discharge lamp , which method comprises the steps of detecting a mechanically induced fluctuation in luminous flux of the lamp occurring as a result of a physical displacement of the discharge arc , determining a characteristic of the mechanically induced fluctuation in luminous flux of the lamp , and adjusting the lamp power on the basis of the determined characteristic to suppress the mechanically induced fluctuation in luminous flux of the lamp . the invention further describes a driver for an arc - discharge lamp , which driver comprises a detecting means for detecting a mechanically induced fluctuation in luminous flux of the lamp occurring as a result of a physical displacement of the discharge arc , a determination unit for determining a characteristic of the mechanically induced fluctuation in luminous flux of the lamp ; and an adjustment unit for adjusting a lamp power on the basis of the determined characteristic to suppress the mechanically induced fluctuation in luminous flux of the lamp . the invention also describes a lighting assembly comprising a high - intensity gas - discharge lamp and such a driver for driving the lamp according to the inventive method .