Now and again something inside the grey-white cloud flickers like a fluorescent lamp behind a curtain, then a streak of lightning shoots sideways across the sky. A vertical bolt flashes directly to the ground. With eastward movement and night time approaching, there is a point where, from the aeroplane window, the orange sunset is reflected in clouds, yet the darkness of dusk is clearly visible further east beyond the colour. As we near Guadalajara, the thunder storm, at roughly the same altitude as the plane, just adds to this unusual scene. A few delays en route means a late arrival, so it’s morning before we get our first chance to…