Sometimes I turn the ignition and get nothing. This happens several times before the 1991 560SEL finally starts, turning the starter slugishly. I complete my trip, turn off the engine, then reignite again immediately without hesitation. The radio and clock reset as if power was lost. Does it sound like solonoid or battery?

__________________
1991 560SEL (254K miles)
1980 Lincoln Mark VI - Givenchy
1979 Lincoln Mark V Collector's Series
1979 Lincoln Town Car Collector's Series
1979 Ford "Effie" Pickup (in gradual transformation to a show/street truck)
1969 Lincoln Mark III (waiting for "Overhaulin" to call)
1989 Lincoln Towncar
2001 Lexus GS300 (spousal unit's daily driver)