Hi there had the same issue with my LS a year ago (Power Steering fluid shooting out of the front spoiler/bumper)
My brother diagosed this for me.
There is a U shaped powersteering cooler pipe running horizontally at the bottom of the radiator behind the bumper, this had corroded badly and had a tiny pin hole leak where there power steering fluid was shooting out from.
May be worth checking.
I got a replacement from Ebay when someone was breaking an LS.