They had to have some kind of understanding, because Lore knew how to communicate with it, that it ws within range to communicate with and just far enough out to not be detected by long-range sensors of the Enterprise. Lore said that he'd make contact and that he will announce himself as "the one called Data".
But as said, there's no indication that the CE understood any of Lore's rantings. It would be natural for it to chase after starships (after all, none had apparently visited the system since the
Tripoli), and the CE might be experienced enough to stalk at optimum range. The CE never responded to Lore's communications in any verifiable way. And the fact that it stopped its futile attack against the ship's shields at roughly the same time Lore came on air could be simple coincidence.
As discussed in a parallel thread, once Lore's so-called plan was put to action, the CE failed to cooperate. There was no attack when Wesley dropped the shields and beamed out something (in this case, Lore); instead, the CE retreated. A major miscommunication there - if indeed there had been communication in the first place!
Actually, he said to "make it so" and Lore took off to do it.
And what did he expect Lore to
do, really? Transporters can be activated by a push of a button on the bridge (even if this simply means sending a command to the transporter crews), so the tasks left for Lore to perform would have been to
1) dig up the tree and get it to a transporter, and
2) supervise the operation, with either the mandate to drop shields and transport, or the mandate to call the bridge and say "We're, oops, I mean, we are ready, Captain. May we proceed?"
That Picard never paid attention to what Lore really was doing is sort of understandable in light of this: it would presumably take time to dig up the tree, and Lore wouldn't contact the bridge until he was done with at least that part of the operation. Picard wouldn't be negligient in supervising Lore's work, then - he'd be in the belief that he
was supervising, and that in this initial harmless gardening stage, there was no major need for close attention.
But that Picard allowed the operation to proceed at all... That's atypical and difficult to justify. Perhaps Picard was merely interested in seeing what the CE would do to a tree?
Timo Saloniemi