Passage: Shortly after 19:00, the German cruiser Wiesbaden had become disabled by a shell from the battlecruiser Invincible; the German battlecruisers made a 16-point turn to the northeast and made for the crippled cruiser at high speed. III Battle Squadron of the German fleet, which contained the most powerful battleships of the German navy, also altered course to assist Wiesbaden. Simultaneously, the British III and IV Light Cruiser Squadrons began a torpedo attack on the German line; while advancing to torpedo range, they smothered Wiesbaden with fire from their main guns. During the turn to the northeast, the British destroyers Onslow and Acasta approached to launch torpedoes at Lützow, though without success. Onslow was hit three times by Lützow's secondary battery and was forced to withdraw. Shortly thereafter, a second destroyer, Acasta launched a torpedo at Lützow that missed; in return, Lützow and Derfflinger fired a barrage of 15 cm shells at Acasta, hitting her twice. At 19:15, the German battlecruisers spotted the British armored cruiser Defence, which had joined the attack on Wiesbaden. Hipper initially hesitated, believing the ship was the German cruiser Rostock, but at 19:16, Kapitän zur See (KzS) Harder, Lützow's commanding officer, ordered his ships' guns to fire. The other German battlecruisers and battleships joined in the melee; Lützow fired five broadsides in rapid succession. In the span of less than five minutes, Defence was struck by several heavy-caliber shells from the German ships. One salvo penetrated the ship's ammunition magazines and, in a massive explosion, destroyed the cruiser.

Question: What time did Lutzow order his troops to fire?
19:16,