Similarly in Hesychius and other lexica, including Apollonius' Homeric Lexicon. From the scholia on Homer, Iliad 18.553, where the dative plural phrase e)n e)lladanoi=si occurs (as part of a description of an agricultural scene depicted on Achilles' new shield: web address 1). Some mss there have ei)ledanoi=si (cf. epsiloniota 102), but double lambda is the usual way of making this noun metrically suitable for hexameter verse: so also Homeric Hymn to Demeter 456 and Hesiod, Shield 291.
Most of the lexica do give the word with double lambda; exceptions like the present entry (and iota 304) give variants that are not independently attested.