A fluent Mal Loye century helped Lancashire take control of the Roses match as they moved on to 228-3.
On a day hit by rain and bad light, Loye was unbeaten on 113 - his 16th first-class hundred - with Stuart Law 59 not out at the other end.
Yorkshire won the toss and bowled but failed to make good use of conditions which favoured pace bowling.
They reduced the visitors to 17-2 but Loye shared a stand of 69 with Brad Hodge before adding 142 with Law.
Only five overs were possibly after tea - 51 were lost in total - but the visitors will be happy with their day's work after an uncertain start.
Captain Mark Chilton fell early on to Deon Kruis, who found some extra bounce in the sixth over to have him juggled and finally caught by Anthony McGrath at second slip.
Fifteen for one then became 17 for two three overs later when Iain Sutcliffe pushed a ball from Jason Gillespie into the on side only to discover that in doing so he had trodden on his stumps.
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Loye and Hodge set about repairing the damage until the introduction of John Blain as second change surprisingly did for the latter.
Blain had already conceded two boundaries to Loye when, with the fourth ball of his spell, the seamer was flattered to bowl Hodge, who under-edged on to his stumps via a lazy looking pull.
There was still appreciable help for the pace bowlers but Blain bowled much too short and Loye made the most of it, hitting 15 fours as he brought up his hundred off 121 deliveries.
His chanceless innings was characterised by authoritative pulls and barely contained a false stroke.
At the other end, Law passed 5,000 runs for Lancashire and made batting look much easier than it should have been in overcast conditions.