Given the nature of a daytime concert, I would go with the manual settings. ISO 80, Shutter speed 100 (for pal version shooting 50p) or 120 (for ntsc version shooting 60p), Aperture anywhere upwards of 2.8 as required, ND if required. Manual focus is probably the way to go as well, otherwise the focus may hunt around if the subject moves from the focus point. Obviously if the day is overcast, overly dark, overly bright etc. and you need more/less light, adjust the Aperture, ND and ISO, but try to leave the Shutter speed alone. Also set the WB to cloudy to give a slightly warmer tone as I find the Auto WB tends to have a blueish cast, or better still use the Kelvin scale to set WB.
It is a great little camera for video, but I would suggest some sort of external recorder for sound, if sound is important and synching up in post.
Hope that helps. You can see some of my LX7 videos here: and here: