The same rule as for if clauses also applies for the ternary operator: It may be split onto several lines, keeping the question mark and the colon at the front.
<?php
$a = $condition1 && $condition2
? $foo : $bar;
$b = $condition3 && $condition4
? $foo_man_this_is_too_long_what_should_i_do
: $bar;
?>